Treatment of cellulosic materials



Patented Apr. 6, 1943- TREATMENTOF cmULosrc MATERIALS 7.

Clifford Collier Wilcock, Saltord, and Charles Percival Tattersfleld, Audenshaw, near Manchester, England, assignors to Courtanlds Limited, London, England, a British company No Drawing. Application March 11, 1941, Serial No. 382,840. InGreat Britain April 4, 1940 d 4 Claims. (01. 111-1s1 This invention relates to the waterproofing of cellulosic materials.

,It is already known to waterproof such materials by means'of paraflin wax. Waterproofing by means of synthetic resins has also been described. Furthermore, it has already been proposed to treat material with a wax emulsion and a resin or resin-forming substances for impartingresistance to creasing and to render material water-repellent and crease-resistingby means of a parailln emulsion in conjunction with an artiflcial resin of the. urea-formaldehyde type, whereby the material remains water-repellent after repeated washing.

According to the present invention the process 1 of treating cellulosic materials comprises applying to the material a wax or fatty acid of the kind hereinafter described and a proportion of a condensation productof cyanamide and formaldehyde insufllcient to cause any substantial improvement in the crease-resisting. properties of the material. 1

The cellulosic material may be natural, such as cotton or linen, or artificially obtained, such as regenerated cellulose from viscose. It may be in the form of. fibres in theloose or as a sliver, continuous or spun yarn, or knitted or woven fabric. Suitable waxes or fatty acids include parailln wax, ceresin wax, Japan wax, beeswax and spermaceti, stearic acidand palmitic acid.

The condensation product of cyanamide and formaldehyde may be produced on or in the fibre as described and claimed in British patent speciiication No. 506,793,111 which case the wax or fatty acid may be applied to the material .along 1 with the cyanamide and formaldehyde'with or without ammonium sulphocyanide at a suitable pH value, and the so-treated material then dried and heated, or the cyanamide and formaldehyde may be applied and, after drying and heating, the material. containing the fully condensed cyanamide-formaldehyde product then passed through an emulsion of the wax or fatty acid. Instead of ammonium sulphocyanide other ammonium salts such as ammonium chloride crammoniumnitrate may be incorporated with the cyanamide formaldehyde product.

Alternatively, the condensation product may be formed and applied from its solution in acid,

preferably acetic acid, as described and claimed in British patent specification No. 515,847. 'In this case the treatment with the wax or fatty acid may be carried out prior to, subsequently to or simultaneously with the application ofthe said condensation product, although the last method will be inapplicable it the addition of the acid solution causes a breakdown of the wax emulsion. The proportion of the condensation product of,

cyanarnide and formaldehyde in the solution with which the, material is treated may conveniently be. 3 per cent or less calculated onthe weight of the material, and of this only a proportion, iorexample one-third, will be abstracted by the ma- Such proportions are terial from the solution. well belowv those necessary to obtain any substantial improvement in the crease-resisting.

properties of the material. H

The treatment according to this invention gives materials with good water-repelling properties which are not substantially affected by scouring or washing, milling, dry-cleaning or dyeing.

The said treatment may be eifected in conjunction with other treatments. For example, aluminium acetate may be added to the treating liquid in order to increase the water-repellency and resistance to dry-cleaning. Again the well known processes for substantially improving the creaseresisting' properties of the material by incorporating suflicient synthetic resin distributed within and substantially not between the individual fibres, may process of the present invention. 1 The following examplesdllustrate methods of carrying out the present invention although the invention is not restricted to these examples- Example 1 4.5 denier matt staple fibre marketed under the registered Trade-Mark "Fibro" is steeped for 10 minutes in sliver form in a mixture of 25 parts of a 3 per cent cyanamide solution and 4 parts of a 40 per cent formaldehyde solution which has been adjusted to a pH value of 6 and then 0.25 part of ammonium sulphocyanide and 0.87 part oi a 30 per cent paraflln wax emulsion added. The sliver is then removed from the mixture, hydroextracted, dried and heated at cent-igrade. The resulting product shows a greater waterrepellency than a similar fibre treated with a wax emulsion of the same concentration alone and is more resistant to soap scouring or steepinglin white spirit at room temperature than the latter.

Example 2 4.5 denier matt staple fibre marketed under the registered Trade-Mark Fibro" is steeped for 10 minutes in silver form in a mixture of 25 parts of a 3 per cent cyanamide solution and 4 parts of a 40 per cent formaldehyde solution which has been adjusted to a pH value or 6 and then 0.25 part of also be used in conjunction with the ammonium sulphocyanide added. The sliver is thenlremoved from the mixture, hydro-extracted. dried and heated at 135 centigrade. It is then steeped for ten minutes in a liquid containing 3 per cent of a 30 per cent wax emulsion and thereafter hydro-extracted and dried. The resulting product has good water repellency which persists after scouring with a 0.5 per cent solution of soap a at 40 centigrade or after, steeping for one hour in white spirit at room temperature.

Example 3 20 partsof the product produced by the interaction of cyanamide and formaldehyde in alkaline solution is dissolved in 200 parts of a ;per

cent acetic acid at the boil; 6.3 parts of this is I further diluted to 200 parts and a piece of fabric made from Fibro yarn is steeped therein for 15 minutes, followed by squeezing, rinsing in cold water and squeezing. The cloth is then worked for 10 minutes in a 1.5 per cent dispersion of parafiln wax at from 50 to 60 centigrade followed by squeezing, drying and ironing. A piece of wet out Fibro cloth is treated with a similar disperslon of waxuunder the same conditions. Comparedwiththis, the former piece possesses high v Erample 4 y 10 grams of paraffln wax of meltingpoint 54 centigrade are emulsified with 1 gram of triethanolamine stearate and 20. cubic centimetres or water. To this is added 3 grams of the product formed by the: interaction of cyanamide and formaldehyde in alkaline solution dissolved in 24 cubic centimetres of 10 per cent acetic acid. The .whole is then diluted with water at 50 centigrade to yield an emulsioncontainingl per cent of wax and 0.3 per center the said reaction product. g

' l/s Fibro yarn at 3 filament denier, bright, is steeped in the emulsion for 10 minutes and then hydro-extracted .and dried. The yarn is waterrepellent and remains so after either scouring twice at 40 centigrade with a 0.5 per cent solution of soap, milling at 50" centigrade for halfan-hour in a solution of 0.5 per cent of soap and 0.25 per cent of soda ash solution, followed by dyeing ior'lzhour at the boil with l per centAzo Geranine 2G8 (Colour Index No. 31) and 2 per cent of formic acid in a liquor ratio of 40 to 1 on the weight of yarn. or steeping for l hourin white spirit at room temperature.

V Example'5 v l/20s Fibro yarn, 3 filament denier, bright,

" is steeped for 10 minutes at 40 centigrade in a 1 per-cent emulsion of paraflin wax of melting point 49 centigrade prepared by emulsifying 10 parts of the wax with-l part of triethanolamine stearate solution adjusted to 8.

in 20 parts of water and subsequently diluting. The yarn is then hydro-extracted and steeped in 20 volumes of a solution prepared by dissolving the alkaline condensation product of cyanamide and formaldehyde in its own weight of acetic acid and diluting until the concentration of the said product is 3 per cent. After steeping for 20 minutes at 50 centigrade the yarn is hydro-extracted and dried.

The water repellency of the yarn which has received the first treatment but not the second is completely removed by scouring in 0.5 percent solution of soap at 40 centigrade for 20 minutes, or steeping for one hour in white spirit at room temperature, whereas the water-repellency of the yarn which has received the two treatments is substantially unaflected by the above treatments with soap solution or white spirit.

Example 6 54 parts of urea are dissolved in 124 parts of 40 per cent formaldehyde and the pH value of the This solution is then boiled for 5 minutes under a reflux condenser, cooled quickly and allowed to stand overnight. It

is then diluted with an equal amount of water and 1 per cent of ammonium chloride is added.

A wax emulsion is prepared by melting 10 parts of parafiin wax of melting point 57 centigrade and homogenising with a hotsolution of 2 parts of gelatine in 20 parts of Water. To this emulsion is added 3 parts of the alkaline'condensation product of cyanamide and formaldehyde, dissolved in an equal weight of acetic acid. Finally the emulsion is diluted to parts with aluminium acetate solution of such strength that the final concentration of A1203 is 20 grams per litre.

To 9 parts of the methylol urea solution is added 1 part of the above emulsion and pieces of 100 per cent Fibro cloth treated in the resulting mixture. The pieces are then dried and finally heated; at centigrade. The material then has improved crease-resisting and waterrepelling properties.

What we claim is:

l. A process of treating cellulosic 'materials I which comprises applying to the material asubstance selected from the group consisting of parafiin wax, ceresin wax, Japan wax, beeswax, spermaceti, stearic acid and palmitic acid and from 0.5 per cent to 6 per cent of a condensation prod- 7 not of cyanamide and formaldehyde.

2. A process as claimed in claim 1, wherein the application of the said condensation product is eflected by impregnating the material with a solution of cyanamide and formaldehyde and causing those compound to there condense.

3. A process as claimed in claim 1, wherein the application of the said condensation product is effected by impregnating the material with a solution in acid of the previously prepared condensation product of cyanamide and formaldehyde.

4. A process as claimed in claim 1, wherein the wax or fatty acid is applied as a dispersion.

CLIFFORD COLLIER WILCOCK. V CHARLES PERCIVAL TATIERSFIELD. 

